You certainly can ship non-free software and free software together, in the general case. I was, of course, talking about the context of the parent comment, which was about (non-free) software that, as a fundamental part of its operation, use free software via a well-defined non-link-time interface. Such as, for example, a GUI text-search tool that, to do its fundamental work, shells out to gnu grep.
My understanding is that the relevant part of the GPLv2 is (with emphasis mine):
"If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it."
I honestly agree it's pretty explicit, but disagree with you about what it says.
IANAL, but I have heard the analysis I gave from two independent sources, one of whom is a lawyer specializing in IP law, and the other of whom used to work with the FSF on policy issues.
As I say, my understanding (given to me by the aforementioned lawyer) is that this has not been tested in court.
My understanding is that the relevant part of the GPLv2 is (with emphasis mine):
"If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it."
I honestly agree it's pretty explicit, but disagree with you about what it says.
IANAL, but I have heard the analysis I gave from two independent sources, one of whom is a lawyer specializing in IP law, and the other of whom used to work with the FSF on policy issues.
As I say, my understanding (given to me by the aforementioned lawyer) is that this has not been tested in court.